Tauern tunnel first and second tubes from the consultant's viewpoint / Tauerntunnel erste und zweite Röhre aus der Sicht des Planers

The first tube of the Tauern tunnel for the A10 Tauern autobahn was constructed in the years 1970 to 1975. The great difficulties with the drive in strongly squeezing rock led to new methods being developed to cope with such rock conditions and represented a significant step forward for the New Austrian Tunnelling Method. After many false starts, the construction of the second tube has been underway since 2006, and the tunnelling work is now complete. About 35 years lie between the tunnelling work for the first and second tubes. This permits a good evaluation of progress in this area. From the designer's viewpoint, the major advances have been in the following areas:
- In the geotechnical design, now systematised through the ÖGG guideline, making it more practical.
- In the quality of the support measures and particularly the shotctrete.
- The greatest step forward is, however, the methods and the implementation of geotechnical surveying (trigonometric) and its rapid and trouble-free evaluation, allowing new methods of interpretation.
This was certainly also the reason why the tunnelling work for the second tube was considerably less eventful than anticipated. The result is that there will be no overruns of time or cost for the second tube